United States Numbered Highway System
The United States Numbered Highway System (often called a U.S. Route or a U.S. Highway) is an integrated network of roads and highways numbered within a nationwide grid in the contiguous United States. As the designation and numbering of these highways were coordinated among the states, they are sometimes called Federal Highways, but the roadways were built and have always been maintained by state or local governments since their initial designation in 1926. The route numbers and locations are coordinated by the American Association of State Highway and Transportation Officials (AASHTO). The only federal involvement in AASHTO is a nonvoting seat for the United States Department of Transportation (USDOT). Generally, north-to-south highways are odd-numbered, with lowest numbers in the east, the area of the founding thirteen states of the United States, and highest in the west. Similarly, east-to-west highways are typically even-numbered, with the lowest numbers in the north, where roads were first improved most intensively, and highest in the south. Major north–south routes have numbers ending in "1" while major east–west routes have numbers ending in "0". Three-digit numbered highways are spur routes of parent highways but are not necessarily connected to their parents. Some divided routes exist to provide two alignments for one route, even though many splits have been eliminated. Special routes, usually posted with a banner, can provide various routes, such as an alternate, bypass or business route, for a U.S. Highway. Before the U.S. Routes were designated, auto trails designated by auto trail associations were the main means of marking roads through the United States. In 1925, the Joint Board on Interstate Highways, recommended by the American Association of State Highway Officials (AASHO), worked to form a national numbering system to rationalize the roads. After several meetings, a final report was approved by the U.S. Department of Agriculture in November 1925. They received complaints from across the country about the assignment of routes, so the Board made several modifications; the U.S. Highway System was approved in November 1926. As a result of compromises made to get the U.S. Highway System approved, many routes were divided, with alignments to serve different towns. In subsequent years, AASHTO called for such splits in U.S. Routes to be eliminated. Expansion of the system continued until 1956, when the Interstate Highway System was formed. After construction was completed, many U.S. Routes were replaced by Interstate Highways for through traffic. Despite the Interstate system, U.S. Highways still form many important regional connections, and new routes are still being added. System details See also: List of United States Numbered Highways is printed on a square blank with a black background. ]] is the only state to use an older cut-out design.]] is also the only state that uses a unique coloring style to differentiate them from the regular U.S. Route shields.]] In general, U.S. Routes do not have a minimum design standard, unlike the later Interstate Highways, and are not usually built to freeway standards. Some stretches of U.S. Routes do meet those standards. Many are designated using the main streets of the cities and towns through which they run. New additions to the system, however, must "substantially meet the current AASHTO design standards". As of 1989, the United States Numbered Highways system has a total length of 157,724 miles (253,832 kilometers). Except for toll bridges and tunnels, very few U.S. Routes are toll roads. AASHTO policy says that a toll road may only be included as a special route, and that "a toll-free routing between the same termini shall continue to be retained and marked as a part of the U.S. Numbered System." U.S. Route 3 (US 3) meets this obligation; in New Hampshire, it does not follow tolled portions of the Everett Turnpike. But U.S. Routes in the system do use parts of four toll roads: * US 51 uses part of the Jane Addams Memorial Tollway in Illinois; the old road is Illinois Route 251. * US 278 uses the tolled Cross Island Parkway in South Carolina; the old road is US 278 Business. * US 412 uses the Cimarron Turnpike in Oklahoma; the old road is US 64. * US 412 also uses the Cherokee Turnpike in Oklahoma; the old road is Alternate US 412. Numbering The two-digit U.S. Routes follow a simple grid in the contiguous United States, in which odd-numbered routes run generally north to south and even-numbered routes run generally east to west. (US 101 is considered a two-digit route, its "first digit" being 10.) The numbering pattern for U.S. Routes was established first: U.S. Routes proceed from low even numbers in the north to high even numbers in the south, and from low odd numbers in the east to high odd numbers in the west. Numbers ending in 0 or 1 (and US 2), and to a lesser extent in 5, were considered main routes in the early numbering, but extensions and truncations have made this distinction largely meaningless. For example, US 6 was a main U.S Route until 1964 the longest route (that distinction now belongs to US 20). In the 1950s, the numbering grid for the new Interstate Highway System was established as intentionally opposite from the US grid insofar as the direction the route numbers increase. Interstate Highway numbers increase from west-to-east and south-to-north, to keep identically numbered routes geographically apart in order to keep them from being confused with one another, and it omits I-50 and I-60 which would potentially collide with US 50 and US 60. Both highway systems still number the routes ending in odd numbered highways running north–south and the even-numbered highways running east–west, although the Interstate System labels its main north–south highways with numbers ending in 5, rather than 1, but also ending in 0 like the U.S. Route System. In the US Highway system, three-digit numbers are assigned to spurs of one or two-digit routes. US 201, for example, splits from US 1 at Brunswick, Maine, and runs north to Canada. Not all spurs travel in the same direction as their "parents"; some are connected to their parents only by other spurs, or not at all, instead only traveling near their parents. As originally assigned, the first digit of the spurs increased from north to south and east to west along the parent; for example, US 60 had spurs, running from east to west, designated as US 160 in Missouri, US 260 in Oklahoma, US 360 in Texas, and US 460 and US 560 in New Mexico. As with the two-digit routes, three-digit routes have been added, removed, extended and shortened; the "parent-child" relationship is not always present. For example, several spurs of the decommissioned US 66 still exist. US 191 travels from border to border although its parent, US 91, has been largely replaced by Interstate 15 (I-15). In addition, US 163, designated in 1970, is nowhere near US 63. The short US 57, approved in 1970, connects to Federal Highway 57 in Mexico, and lies west of former US 81. Several routes approved since 1980 do not follow the numbering pattern: *US 400, approved in 1994, has no "parent" since there is no US 0 or US 100. *US 412, approved in 1982, is nowhere near US 12. *US 425, approved in 1989, is nowhere near US 25. While AASHTO guidelines specifically prohibit Interstate Highways and U.S. Routes from sharing a number within the same state (which is why there are no Interstates 50 or 60), the initial Interstate numbering approved in 1958 violated this with I-24 and US 24 in Illinois and I-40, I-80, US 40 and US 80 in California (US 40 and US 80 were removed from California in its 1964 renumbering). Some recent and proposed Interstates, some of them out of place in the grid, also violate this: I-41 and US 41 in Wisconsin (which run concurrently), I-49 and US 49 in Arkansas, I-69 and US 69 in Texas, and I-74 and US 74 in North Carolina (which run concurrently). Some two-digit numbers have never been applied to any U.S. Route, including 39, 47, and 86. Category:United States Numbered Highway System Category:Transport systems Category:Types of roads Category:United States Numbered Highways Category:Roads and highways in the United States